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The parallelogram has a base whose length is half the circumference of the circle, and
its height is the radius of the circle. Based on the information above, the area of the
building = base x height
= ....x .....
= ....
Based on the above activity, we know that the area of the shape is the area of a circle,
so the area of the circle is the area bounded by the arc or circumference of a circle. In
calculating the area of a circle is not difficult. You can use two ways to calculate the
area of a circle, if you know the radius (r) or if you know the diameter (d) as follows:

L = π (if known radius)

L = ¼ π (if known diameter)

with
L = area of circle
r = radius
d = diameter

by

or 3,14

Example :

1. A circular playground has a circumference of 176 m. How big is the playground?
Alternative Solution:

Is known
Perimeter of the garden = 176 meters

Q: What is the area of the playground?
Circumference of the garden = circumference of circle

Circumference of the garden = 2 π r
176 = 2 π r (known diameter)

176 = x r

176 x 7 = 22 x 2 x r

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